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In this paper, we estimate the cross-correlation power spectra between the Planck 2018 cosmic microwave background (CMB) temperature anisotropy map and the unresolved $gamma$-ray background (UGRB) from the 9-years Fermi-Large Area Telescope (LAT) data. In this analysis, we use up to nine energy bins over a wide energy range of [0.631, 1000] GeV from the Fermi-LAT UGRB data. Firstly, we find that the Fermi data with the energy ranges [1.202, 2.290] GeV and [17.38, 36.31] GeV show the positive evidence for the Integrated Sachs-Wolfe (ISW) effect at $1.8sigma$ confidence level, and the significance would be increased to $2.7sigma$ when using these two energy bins together. Secondly, we apply the single power-law model to normalize the amplitude and use all the nine Fermi energy bins to measure the significance of the ISW effect, we obtained ${rm A_{amp}}=0.95 pm 0.53$ ($68%$ C.L.). For the robustness test, we implement a null hypothesis by randomizing the Fermi mock maps of nine energy bins and obtain the non-detection of ISW effect, which confirms that the ISW signal comes from the Fermi-LAT diffuse $gamma$-ray data and is consistent with the standard $Lambda$CDM model prediction essentially. We use a cross-correlation coefficient to show the relation between different energy bins. Furthermore, we vary the cut ranges $|b|$ of galactic plane on the mask of Fermi map and carefully check the consequent influence on the ISW signal detection.
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We present a map of the Cosmic Microwave Background (CMB) anisotropies induced by the late Integrated Sachs Wolfe effect. The map is constructed by combining the information of the WMAP 7-yr CMB data and the NRAO VLA Sky Survey (NVSS) through a linear filter. This combination improves the quality of the map that would be obtained using information only from the Large Scale Structure data. In order to apply the filter, a given cosmological model needs to be assumed. In particular, we consider the standard LCDM model. As a test of consistency, we show that the reconstructed map is in agreemet with the assumed model, which is also favoured against a scenario where no correlation between the CMB and NVSS catalogue is considered.
Based on CMB maps from the 2013 Planck Mission data release, this paper presents the detection of the ISW effect, i.e., the correlation between the CMB and large-scale evolving gravitational potentials. The significance of detection ranges from 2 to 4 sigma, depending on which method is used. We investigate three separate approaches, which cover essentially all previous studies, as well as breaking new ground. (i) Correlation of the CMB with the Planck reconstructed gravitational lensing potential (for the first time). This detection is made using the lensing-induced bispectrum; the correlation between lensing and the ISW effect has a significance close to 2.5 sigma. (ii) Cross-correlation with tracers of LSS, yielding around 3 sigma significance, based on a combination of radio (NVSS) and optical (SDSS) data. (iii) Aperture photometry on stacked CMB fields at the locations of known large-scale structures, which yields a 4 sigma signal when using a previously explored catalogue, but shows strong discrepancies in amplitude and scale compared to expectations. More recent catalogues give more moderate results, ranging from negligible to 2.5 sigma at most, but with a more consistent scale and amplitude, the latter being still slightly above what is expected from numerical simulations within LCMD. Where they can be compared, these measurements are compatible with previous work using data from WMAP, which had already mapped these scales to the limits of cosmic variance. Plancks broader frequency coverage confirms that the signal is achromatic, bolstering the case for ISW detection. As a final step we use tracers of large-scale structure to filter the CMB data, presenting maps of the ISW temperature perturbation. These results provide complementary and independent evidence for the existence of a dark energy component that governs the current accelerated expansion of the Universe.
We study the late-time Integrated Sachs-Wolfe (ISW) effect in $f(R)$ gravity using N-body simulations. In the $f(R)$ model under study, the linear growth rate is larger than that in general relativity (GR). This slows down the decay of the cosmic potential and induces a smaller ISW effect on large scales. Therefore, the $dotPhi$ (time derivative of the potential) power spectrum at $k<0.1h$/Mpc is suppressed relative to that in GR. In the non-linear regime, relatively rapid structure formation in $f(R)$ gravity boosts the non-linear ISW effect relative to GR, and the $dotPhi$ power spectrum at $k>0.1h$/Mpc is increased (100$%$ greater on small scales at $z=0$). We explore the detectability of the ISW signal via stacking supercluster and supervoids. The differences in the corresponding ISW cold or hot spots are $sim 20%$ for structures of $sim 100$Mpc/$h$. Such differences are greater for smaller structures, but the amplitude of the signal is lower. The high amplitude of ISW signal detected by Granett et al. can not explained in the $f(R)$ model. We find relatively big differences between $f(R)$ and GR in the transverse bulk motion of matter, and discuss its detectability via the relative frequency shifts of photons from multiple lensed images.
This paper presents a study of the ISW effect from the Planck 2015 temperature and polarization data release. The CMB is cross-correlated with different LSS tracers: the NVSS, SDSS and WISE catalogues, and the Planck 2015 lensing map. This cross-correlation yields a detection at $4,sigma$, where most of the signal-to-noise is due to the Planck lensing and NVSS. In fact, the ISW effect is detected only from the Planck data (through the ISW-lensing bispectrum) at $approx 3,sigma$, which is similar to the detection level achieved by combining the cross-correlation signal coming from all the catalogues. The ISW signal allow us to detect $Omega_Lambda$ at more than $3,sigma$. This cross-correlation analysis is performed only with the Planck temperature data, since the polarization scales available in the 2015 release do not permit significant improvement of the CMB-LSS cross-correlation detectability. Nevertheless, polarization data is used to study the anomalously large ISW signal previously reported through the stacking of CMB features at the locations of known superstructures. We find that the current Planck polarization data do not exclude that this signal could be caused by the ISW effect. In addition, the stacking of the Planck lensing map on the locations of superstructures exhibits a positive cross-correlation with these large-scale structures. Finally, we have improved our previous reconstruction of the ISW temperature fluctuations by combining the information encoded in all the previously mentioned LSS tracers. In particular, we construct a map of the ISW secondary anisotropies and the corresponding uncertainties map, obtained from simulations. We also explore the reconstruction of the ISW anisotropies caused by the LSS traced by the 2MPZ survey by directly inverting the density field into the gravitational potential field.
Cosmic structures leave an imprint on the microwave background radiation through the integrated Sachs-Wolfe effect. We construct a template map of the linear signal using the SDSS-III Baryon Acoustic Oscillation Survey at redshift 0.43 < z < 0.65. We verify the imprint of this map on the Planck CMB temperature map at the 97% confidence level and show consistency with the density-temperature cross-correlation measurement. Using this ISW reconstruction as a template we investigate the presence of ISW sources and further examine the properties of the Granett-Neyrinck-Szapudi supervoid and supercluster catalogue. We characterise the three-dimensional density profiles of these structures for the first time and demonstrate that they are significant structures. Model fits demonstrate that the supervoids are elongated along the line-of-sight and we suggest that this special orientation may be picked out by the void-finding algorithm in photometric redshift space. We measure the mean temperature profiles in Planck maps from public void and cluster catalogues. In an attempt to maximise the stacked ISW signal we construct a new catalogue of super-structures based upon local peaks and troughs of the gravitational potential. However, we do not find a significant correlation between these structures and the CMB temperature.
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